Thin film approach to biocatalysis

Taking an unconventional approach to biocatalysis has allowed scientists in Italy to improve enzyme recyclability with a solvent-free reaction mixture. And by emphasising a need to design processes, biocatalysts and reactors together, instead of separately, they hope to widen the industrial applications of nature’s catalysts.

Lucia Gardossi, from the University of Trieste in Italy, has been investigating solvent-free reaction mixtures, which appeal to industry because of their comparably small production volumes and lack of organic solvents to dispose of. Although their efficiency and selectivity are attractive, biocatalysed versions of industrial reactions are rarely economically viable. The typically viscous reaction mixtures require vigorous mixing, which damages the enzymes and limits their recyclability.

Gardossi’s team’s solution involves a thin film with enzymes covalently immobilised on resin carriers that they tested on a lipase-driven polyesterification. This system preserved the enzyme’s integrity, as the reaction mixture does not need to not stirred, improving recyclability.

The research emphasised the need to stop trying to use enzymes as normal catalysts. Instead of using general reactors, under standard conditions, processes need to be designed specifically to suit biocatalysts. ‘In many cases process engineering, enzymology and organic chemistry are treated and developed in parallel. In the future, if we want to design very efficient processes, we will have to integrate these from the beginning through a multidisciplinary approach,’ explains Gardossi.

Polona Znidarsic, who researches ways to incorporate microreactor technology into biotechnology, at the University of Ljubljana in Slovenia, praises the researchers’ achievements: ‘By addressing several key parameters, this study represents an important step towards sustainable and economical industrial polyester production.’ 

The group are now looking to improve the sustainability of their system, by replacing the current petroleum-based carrier resins with ones made from biomass.